This invention relates to a system and method for providing feedback to a driver of a hybrid electric vehicle and more particularly, to a system and a method which provides feedback to a driver when the powertrain of a hybrid electric vehicle is active and the vehicle""s engine is stopped.
A hybrid electric vehicle utilizes both an internal combustion engine and one or more electric motors to generate power and torque to the vehicle""s drive train. The electric motor within a hybrid electric vehicle provides the vehicle with additional degrees of freedom in delivering the driver-demanded torque over conventional vehicles which use only internal combustion engines to deliver torque. Particularly, hybrid electric vehicles have the flexibility of using the electric motor(s) as the sole source of torque at low load operating conditions. In this manner, the vehicle is able to significantly improve fuel economy and emissions.
The electric motor(s) within hybrid electric vehicles run very xe2x80x9csmoothlyxe2x80x9d and are often inaudible to a driver. Thus, when the engine is xe2x80x9cturned offxe2x80x9d or stopped during low load or idling conditions, a driver will experience very little noise or vibration. Drivers who are accustomed to conventional vehicles often expect and/or anticipate a certain level of noise and/or vibration when a vehicle""s powertrain is active. This noise and/or vibration is typically produced by the idling of the vehicle""s internal combustion engine. However, when a hybrid electric vehicle is being braked in low load or idling conditions, and has turned off its internal combustion engine, such noise and vibration will not be experienced by a driver, due to the relatively quiet and smooth operation of the electric motor. Therefore, hybrid electric vehicles will have a different xe2x80x9cfeelxe2x80x9d than conventional vehicles in such situations.
The present invention provides a system and a method which provides feedback to a driver of a hybrid electric vehicle when the powertrain of the vehicle is active and the vehicle""s engine is stopped, thereby giving the hybrid electric vehicle a xe2x80x9cfeelxe2x80x9d similar to a conventional vehicle.
It is a first non-limiting advantage of the invention to provide a system and a method which provides feedback to a driver regarding the operational status of the vehicle""s powertrain.
It is a second non-limiting advantage of the invention to provide a system and method for notifying a driver of a hybrid electric vehicle of the operational status of the vehicle""s powertrain when the powertrain of the vehicle is active and the vehicle""s engine is stopped.
It is a third non-limiting advantage of the invention to provide a hybrid electric vehicle including a feedback system which detects when the vehicle""s engine is stopped and which provides feedback to a driver regarding the operational status of the vehicle""s powertrain in response to such a detection.
According to a first aspect of the present invention, a feedback system is provided for use with a hybrid electric vehicle of the type having a drive line, an electric machine which is operatively coupled to the drive line and which selectively provides torque to the drive line, and an engine which is operatively coupled to the drive line and which selectively provides torque to the drive line. The feedback system includes a controller which is communicatively coupled to the engine and to the electric machine, the controller being effective to determine when the engine is stopped and the electric machine is in an active torque producing state, and based upon the determination to communicate signals to the electric machine, the signals being effective to cause the electric machine to transmit torque pulsations to the drive line, thereby notifying a driver of the vehicle of the active torque producing state of the electric machine.
These and other features, aspects, and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.